Freehand Endoscopic Fistulotomy Guided by Perineal Ultrasound in Crohn's Perianal Abscess: A Day-Care Alternative to Surgery Allowing Continuation of Biologics

An 18-year-old male with fistulizing Crohn's disease involving the ileocolonic region and rectum had a right-sided intersphincteric fistula at the 11 o'clock position, managed previously by endoscopic seton placement.[1] After three induction doses of infliximab, he presented with pain, induration, and purulent discharge from the left perianal region (at the 3 o'clock position). The next infliximab dose was due in 1 week.

Point-of-care transperineal ultrasound (TPUS; Linear probe 2–9 MHz, Samsung RS80 EVO, Samsung India Electronic Pvt. Ltd.) revealed a 10 × 9 × 9 mm hypoechoic abscess without fistulous communication ([Fig. 1A, B]). Accurate point-of-care TPUS avoided the need for costly magnetic resonance imaging (MRI) pelvis, which is often requested before intervention and can delay treatment. On the same day, under conscious sedation, endoscopic freehand fistulotomy was performed using a needle knife (Boston Scientific, Marlborough, United States) connected to an electrosurgical generator (VIO 300D, ERBE Elektromedizin GmbH, Tübingen, Germany) with Endocut I current (effect 3, cut duration 1, cut interval 3).[2] The knife was held freehand between the index finger and thumb like a pen, rather than through-the-scope, to make two stellate mucosal incisions over the indurated area, facilitating pus drainage ([Fig. 1C, F]; [Video 1]).

Video 1 Point-of-care transperineal ultrasound localizing a small left perianal abscess in Crohn's disease, followed by freehand endoscopic fistulotomy with a needle knife, achieving immediate pus drainage and seton removal in a day-care setting without interrupting biologic therapy.

Fig. 1 (A) Point-of-care transperineal ultrasound (TPUS) showing a well-defined hypoechoic lesion in the left perianal region (3 o'clock position). (B) Color Doppler TPUS confirming absence of significant internal vascularity, consistent with a small abscess. (C) Endoscopic view of the left perianal swelling corresponding to the ultrasound finding. (D) Initiation of freehand fistulotomy using a needle knife (Boston Scientific, Marlborough, United States) connected to an electrosurgical generator (VIO 300D, ERBE Elektromedizin GmbH, Tübingen, Germany) with Endocut I settings (effect 3, cut duration 1, cut interval 3), held between the index finger and thumb like a pen. (E) Immediate drainage of pus following stellate mucosal incision. (F) Post-procedure view showing the drained abscess cavity.

The pre-existing seton at the 11 o'clock position was removed to promote closure and avoid epithelialization of the earlier fistula. Aseptic care with povidone–iodine dressing and intravenous cefoperazone–sulbactam (1.5 g) plus metronidazole (500 mg) immediately after the procedure, followed by oral ciprofloxacin (500 mg twice daily for 8 weeks), was given along with continued infliximab and azathioprine. Although local antibiograms show only modest fluoroquinolone sensitivity, ciprofloxacin is routinely used in perianal Crohn's disease protocols for both antimicrobial and anti-inflammatory benefits, and the patient responded well without adverse effects. The patient was discharged the same day and received his scheduled infliximab dose without delay. This allowed safe continuation of biologics without interruption, which is rarely feasible after surgical drainage. At the 2-month follow-up, the patient had complete resolution of symptoms (no pain or discharge). Repeat perineal ultrasound confirmed absence of residual abscess and reduced fistula tract vascularity, while the patient remained on infliximab maintenance.

Practical Implications for Endoscopists

• Perineal ultrasound allows accurate localization of small abscesses, enabling same-day drainage without delaying biologics.[3]

• Endoscopic freehand fistulotomy is a safe, minimally invasive alternative to surgical drainage in select Crohn's disease cases.[4] [5]

• Endoscopic retrograde cholagiopancreatography accessories such as needle knives can be repurposed for extra-luminal use to access and drain perianal collections.[2] [3]

• Seton removal is advisable once adequate drainage and healing are achieved to prevent epithelialization and chronicity.

• Day-care endoscopic drainage reduces hospital stay and overall cost, avoids MRI pelvis in many cases, and prevents unnecessary interruption of ongoing biologic therapy.[2]

 

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Conflict of Interest

P.P. received consultancy fee from Johnson and Johnson, and other authors declare no potential conflict of interest related to the report.

Patient's Consent

Written informed consent was taken from the patient for the publication of the information and imaging.

• References

• 1 Pal P, Rebala P, Nabi Z. et al. Endoscopic setons placement for complex perianal fistulizing Crohn's disease by fistuloscopy using ultra-thin endoscope introduced into fistula cavity. J Dig Endosc 2023; 14 (04) 245-246
• 2 Pal P, Rebala P, Gupta R, Tandan M, Reddy DN. Endoscopic fistulotomy (through the scope and freehand) as a salvage procedure for recurrent perianal fistula with abscess postsurgery in Crohn's disease. J Dig Endosc 2024; 15 (04) 256-257
• 3 Pal P, Mateen MA, Gupta R, Tandan M, Reddy DN. multifaceted endoscopic approach (stricturotomy, balloon dilation, fistulotomy, and seton placement) guided by intestinal ultrasound to avert surgery in complicated Crohn's disease during lactation. Inflamm Bowel Dis 2025; 31 (09) 2602-2603
• 4 Kochhar G, Shen B. Endoscopic fistulotomy in inflammatory bowel disease (with video). Gastrointest Endosc 2018; 88 (01) 87-94
• 5 Pal P, Mateen MA, Gupta R, Tandan M, Reddy DN. Transperineal ultrasound-guided endoscopic sinusotomy for recurrent perianal sinus in Crohn disease. ACG Case Rep J 2025; 12 (07) e01769

Publication History

Article published online:
16 October 2025